Heart stimulator and heart-powered energy supply therefor

ABSTRACT

A device for supplying electrical energy to a heart stimulator which is formed as an air-tight casing arranged to be placed within the human body in close proximity to the heart muscle. The casing has housed therein an annularly arranged magnetic circuit with a rotor arranged in a gap of the circuit. A rotary piston is accommodated within a piston chamber having four compartments divided in pairs. One of the pair is connected via a flexible tube to a first flexible bag arranged at the tip of the heart and the other pair communicates via another flexible hose to a second flexible elastic bag. The elastic bags contain fluid which communicate alternately between the pairs of compartments within the chamber so that upon the pumping action of the heart the piston is caused to oscillate in a rotary motion and mechanical coupling means are connected between the piston and a driving member mounted coaxially with the rotor so as to drive the rotor thereby producing electrical signals in response to the movement of the heart.

United States Patent [15] 3,693,625 [451 Sept. 26, 1972 Auphan [54]HEART STIMULATOR AND HEART- POWERED ENERGY SUPPLY THEREFOR [72]Inventor: Michel Joseph Auphan, Courbevoie,

France [73] Assignee: U.S. Philips Corporation, New

York, N.Y.

[22] Filed: May 1, 1970 211 App]. No.: 33,745

[30] Foreign Application Priority Data May 13, 1969 France "6 915527[52] U.S. Cl. ..l28/4l9 P, 128/419 B [51] Int. Cl. ..A61n H36 [58] FieldofSearch...128/1R, 419 P, 419 R; 310/37 [56] References Cited UNITEDSTATES PATENTS 3,486,506 12/1969 Auphan "128/419 P 3,563,245 2/1971McLean ..l28/4l9 P 1,061,624 5/1913 Moere ..310/37 PrimaryExaminer-William E. Kamm Attorney-Frank R. Trifari [5 7] ABSTRACT Adevice for supplying electrical energy to a heart stimulator which isformed as an air-tight casing arranged to be placed within the humanbody in close proximity to the heart muscle. The casing has housedtherein an annularly arranged magnetic circuit with a rotor arranged ina gap of the circuit. A rotary piston is accommodated within a pistonchamber having four compartments divided in pairs. One of the pair isconnected via a flexible tube to a first flexible bag arranged at thetip of the heart and the other pair communicates via another flexiblehose to a second flexible elastic bag. The elastic bags contain fluidwhich communicate alternately between the pairs of compartments withinthe chamber so that upon the pumping action of the heart the piston iscaused to oscillate in a rotary motion and mechanical coupling means areconnected between the piston and a driving member mounted coaxially withthe rotor 50 as to drive the rotor thereby producing electrical signalsin response to the movement of the heart.

. 7 Claims, 4 Drawing Figures HEART STIMULATOR AND HEART-POWERED ENERGYSUPPLY THEREFOR This invention relates to a supply device for anintracorporal heart stimulator in the domain of medical prostheses.

Cardiac stimulators used for some diseases provide electric pulses tothe myocardium by electrodes, different sources of energy are availablefor feeding these stimulators.

It is now common practice to use a battery within the body, but thisinvolves two disadvantages: on the one hand the longevity of a batteryis limited and on the other hand rupture of the flexible wiresconnecting the battery to the stimulator may occur due to shaking by theheart beat.

Research made on the sources of energy suitable for such uses tends toobviate these disadvantages by developing an autonomic source of energy,which will be substantially independent of time.

' In this respect research has been made for developing batteries havingelectrodes consumable by biological liquids. However, the longevity ofthese electrodes and any toxic effects they may have on the organismcannot be guaranteed.

Also, the use of thermal sources taking their energy from nuclearreaction involves many problems relating to either the dangers of thecirculation of a radioactive material or the heat exchange at hightemperatures also the cost of an apparatus based on this principle wouldbe prohibitive I The use of the mechanical energy of the heart proposedin various methods should lead to an interesting solution. In fact,since the heart gives off about 15 W in contracting it must be capableof supplying the few hundred microwatts required for feeding astimulator.

However, the mecano-electric transformation tests on piezo-electricmaterials have not produced the desired results. Since the chargesaccumulated at each mechanical deformation of the piezo-electric bodiesare low, these deformations have to be accumulated to the highestpossible frequency for obtaining a sufficient total energy.

A different solution has been described by the Applicant in French Pat.No. 1,460,772 and the Patent of Addition Nr. 92 782. The apparatusproposed forms not only an electric current generator but also a pulsegenerator for stimulating the heart. it comprises in an air-tight box amagnetic circuit, in the gap of which a rotor is adapted to oscillatebetween two pivots. An oscillation of the box produded by the movementof the heart causes the rotor to pass from an unstable position to astable position and during this movement a sequence of rapidoscillations of the rotor induces in the magnetic circuit an oscillatorycurrent of decreasing amplitude. For transmitting the movement of theheart the box comprises a pendulum associated with a rotatable piececoaxial to said rotor and provided with a contact finger whichco-operates with a pin of said rotor. This system, however, can onlyprovide pulses at a predetermined frequency usually of about 1 Hz. Formany cases it is, however, desirable to have available a system ofvariable frequency so that the heart may obtain pulses at differentrhythms.

The present invention based on the same principle of mecano-electrictransformation provides a supply device for an intracorporal heartstimulator, which may be of the conventional type.

The supply device is formed by a member converting mechanical energyinto electric energy and comprises an oscillatory rotor arranged in thegap of a magnetic circuit and means for transmitting the movement of theheart to said rotor, which means comprise a rotatable piece coaxial tosaid rotor and provided with at least one mechanical contact member fordriving said rotor.

According to the invention said means further comprises a rotatablepiston mechanically coupled with the rotatable piece and a membercontrolling the displacements of said piston in accordance with themovements of the heart.

Various characteristics of the invention will be apparent from thefollowing description given by way of example with reference to theaccompanying drawings, which show in FIG. 1 an elevation of the opencasing comprising the supply device in accordance with the invention;

in FIG. 2 a schematic view of the rotatable piston shown at the centerof FIG. 1;

in, FIG. 3 an over-all view of the casing and the transmission of themovements of the heart; and in FIG. 4 a schematic diagram showing thestimulator.

An airtight casing l accommodates an annular magnetic circuit 2aassociated with a winding 2b, the gap accommodating a rotor 3. Twoauxiliary magnets 4 of the kind described in the aforesaid PatentSpecification produce a magnetic field at right angles to the axis ofthe rotor and hence a return-couple for the latter.

The rotor is provided with a driving pin 5 co-operating with a finger 6of a rotatable piece 7 which is coaxial to the rotor, the pin 5 and thefinger 6 forming the mechanical contact elements for driving said rotor.The

- rotatable piece is provided with a gear wheel 8 in mesh with the gearwheel 9 associated with a rotatable piston 11, mounted along the axis AAof the casing 1 inside the annular magnetic circuit. The space 12accommodating the piston 11 is divided into four chambers 13a, 13b, 14aand 14b of pairwise equal, variable volumes. These chambers (see FIGS. 2and 3) are connected, as far as the first two are concerned by theflexible tube 15 with a plastic bag 18 arranged on the tip of the heart17, the two others, by the flexible tube 16 with an elastic bag 19 ofexpansion.

Initially the bag 18 is filled with a liquid. At each systole the bag 18is compressed between the tip of the heart and the surrounding tissues;the liquid is thus expelled into the flexible tube 15, it traverses thespace 12 and emanates from the tube 16 towards the bag 19. After thesystole the tension of the second elastic bag pushes the liquid back tothe first bag, which is no longer subjected to the pressure of the tipof the heart.

During each reciprocatory flow of the liquid, the rotatable piston l lis caused to perform an alternating movement which is transmitted by thegear wheels and produces the oscillation of the rotor under the actionof the couple produced by the magnets 4.

The winding 2b of the magnetic circuit 2a is connected to the terminalsof a first capacitor, so that an oscillatory circuit is formed. If thefrequency of the latter lies near the oscillation frequency of therotor, an automatic transmission of energy is obtained from the rotor tothe oscillatory circuit.

Each time when the energy reaches its maximum level, it is transmitted,for example, by an electric switch 24, to a second capacitor 25 forfeeding a stimulator 26 of conventional type.

The switch 24, the capacitor 25 and the stimulator 26 may beaccommodated inside the casing 1 near the rotatable piston for instance.(not shown for the sake of clarity).

The pulses generated by the stimulator 26 are transmitted via leads 27and 28 to electrodes schematically indicated by arrows 29 and 30, one ofthese electrodes may be formed by the casing l,-whereas the other (30,see FIG. 3) may be fixed to the flexible bag 18, when the liquid isconductive. a

In order to ensure a perfect seal between the space 12 and theassemblyof the device the driving system is formed by a magneticcoupling so that a shaft traversing the casing is not required.

For this purpose the piston 11 is made of magnetic material andassociated with two external, symmetrical magnets.

The invention may be used in the treatment of given cardial diseases byprostheses.

What is claimed is:

l. A device for supplying energy for an intracorporal heart stimulator,comprising an airtight casing to be placed within the human body, anannularly arranged magnetic circuit housed within said casing, a windingcoupled to said magnetic circuit to produce electrical energy saidcircuit having a gap therein, a rotor arranged in said gap foroscillatory movement, a multicompartment piston chamber arranged withinsaid magnetic circuit, a piston mounted for rotatable movement withinsaid chamber about an axis of rotation parallel and eccentric to theaxis of rotation of said rotor, hydraulic means connected with saidchamber for transmitting pulses thereto in response to movements of theheart so as to cause rotational displacement of said piston inaccordance therewith, a driving member rotatably mounted coaxially withsaid rotor and having means contacting said rotor for driving same, andmechanical coupling means for causing movement of said driving member inresponse to rotational movement of said piston so that when said pistonis rotatably driven as a result of heart movement said driving memberwill be caused to rotate and cause oscillatory movement of said rotor soas to produce electrical energy. I

2. The device according to claim 1 wherein said piston chamber comprisesfirst, second, third and fourth compartments, the volume of said firstand third compartments being variable and equal to each other, thevolume of said second and fourth compartments being variable and equalto each other and wherein said hydraulic means comprises a firstflexible bag arranged on the tip of the heart, a first flexible liquidcirculation tube connected to said first flexible bag and communicatingwith said first and third compartments, a second elastic bag ofexpansion and a second flexible liquid circulation tube connected tosaid second elastic bag of expansion and communicating with said secondand fourth compartments.

3. The device according to claim 1 further comprising at least onemagnet disposed near said rotor for roducin a ma etic field ndicular tosaid rotor. p 4. The devic e according claim 1 wherein said piston ismounted for rotation about an axis of the casing which is filled withair, and wherein said piston is made of magnetic material and furthercomprising a pair of magnets arranged symmetrically outside of saidpiston chamber so as to form a magnetic coupling thereby producing adrive for the piston.

5. The device according to claim 1 further comprising a capacitorconnected to said winding and forming an oscillatory circuit for thetransmission of the mechanical energy of the rotor.

6. The device according to claim 1 wherein said mechanical couplingmeans for causing movement of said driving member in response torotational movement of said piston comprises a first gear wheel arrangedon said driving member and a second gear wheel associated with saidpiston and arranged in mesh with said first gear wheel.

7. The device according to claim I further comprising a heart stimulatorcarried within said casing, an energy accumulator connected to saidstimulator and a switch for connecting said oscillatory circuit to saidenergy accumulator, one of the electrodes of said stimulator beingformed by said casing and the other electrode being fixed to saidflexible bag at the tip of

1. A device for supplying energy for an intracorporal heart stimulator,comprising an airtight casing to be placed within the human body, anannularly arranged magnetic circuit housed within said casing, a windingcoupled to said magnetic circuit to produce electrical energy saidcircuit having a gap therein, a rotor arranged in said gap foroscillatory movement, a multicompartment piston chamber arranged withinsaid magnetic circuit, a piston mounted for rotatable movement withinsaid chamber about an axis of rotation parallel and eccentric to theaxis of rotation of said rotor, hydraulic means connected with saidchamber for transmitting pulses thereto in response to movements of theheart so as to cause rotational displacement of said piston inaccordance therewith, , a driving member rotatably mounted coaxiallywith said rotor and having means contacting said rotor for driving same,and mechanical coupling means for causing movement of said drivingmember in response to rotational movement of said piston so that whensaid piston is rotatably driven as a result of heart movement saiddriving member will be caused to rotate and cause oscillatory movementof said rotor so as to produce electrical energy.
 2. The deviceaccording to claim 1 wherein said piston chamber comprises first,second, third and fourth compartments, the volume of said first andthird compartments being variable and equal to each other, the volume ofsaid second and fourth compartments being variable and equal to eachother and wherein said hydraulic means comprises a first flexible bagarranged on the tip of the heart, a first flexible liquid circulationtube connected to said first flexible bag and communicating with saidfirst and third compartments, a second elastic bag of expansion and asecond flexible liquid circulation tube connected to said second elasticbag of expansion and communicating with said second and fourthcompartments.
 3. The device according to claim 1 further comprising atleast one magnet disposed near said rotor for producing a magnetic fieldperpendicular to said rotor.
 4. The device according to claim 1 whereinsaid piston is mounted for rotation about an axis of the casing which isfilled with air, and wherein said piston is made of magnetic materialand further comprising a pair of magnets arranged symmetrically outsideof said piston chamber so as to form a magnetic coupling therebyproducing a drive for the piston.
 5. The device according to claim 1further comprising a capacitor connected to said winding and forming anoscillatory circuit for the transmission of the mechanical energy of therotor.
 6. The device according to claim 1 wherein said mechanicalcoupling means for causing movement of said driving member in responseto rotational movement of said piston comprises a first gear wheelarranged on said driving member and a second gear wheel associated withsaid piston and arranged in mesh with said first gear wheel.
 7. Thedevice according to claim 1 further comprising a heart stimulatorcarried within said casing, an energy accumulator connected to saidstimulator and a switch for connecting said oscillatory circuit to saidenergy accumulator, one of the electrodes of said stimulator beingformed by said casing and the other electrode being fixed to saidflexible bag at the tip of the heart.